Focusing drive for a microscope with flexible drive shaft

ABSTRACT

The drive has a manual coarse/fine focusing device using a gear drive and additional fine focusing using a motor. The latter is effected through an eccentric cam, rotatingly supported in a guide plate and coupled with the motor. A ball bearing rigidly joined with the object holder and the microscope stage rests on the eccentric cam. During operation of the motor, only the ball bearing and, thus, the microscope stage are raised or lowered; the gear drive for manual focusing remains stationary.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a drive mechanism for the focusing of amicroscope and more particularly to such a drive mechanism in whichmanual adjustments are made with a gear drive, and an additional fineadjustment is made by a motor through a control element.

2. Discussion of Related Art

A motor drive for the sharp focusing of microscopes with coarse and fineadjustments is disclosed in DE-P No. 22 62 612. The coarse and fineadjustments are effected by use of a common spindle, with the drive forthe fine focusing being engageable and disengageable with the spindle.Two bidirectional motors are provided, one of which performs the coarseadjustment and the other of which performs the fine adjustment. Acontrol element effects the engagement of the drive means with the fineadjustment motor by means of a cam and also controls the starting andstopping of the motors. The coarse adjustment motor has a shaft parallelto the spindle. A gear is mounted on this shaft and constantly mesheswith a gear mounted on the spindle. The fine adjustment motor issupported on a carrier with its shaft perpendicular to the spindle. Thecarrier is pivotable against the tension of a spring. The fineadjustment motor shaft carries a worm, which meshes with a worm wheelseated on the spindle.

A coarse and fine focusing device is disclosed in JA No. 41-9420 whichmay be operated both manually and with a motor. The arrangement requiresno coupling, but needs an additional gear drive for the motor.Furthermore, a vertical adjustment of the control knobs for manualfocusing takes place simultaneously with the actuation of the drive.

In FR No. 1 316 033, a focusing mechanism for a microscope is disclosedwhich may be actuated manually and by means of a motor. Two separatedrive shafts, acting on separate guides, for the manual coarse and fineadjustment are connected through two friction clutches and flexibleshafts with two motors, which effect the coarse and fine motor focusing.Here again the adjusting knob for fine focusing travels upward ordownward upon the actuation of the coarse adjustment.

Finally, DE-OS 26 27 486 discloses a coarse and fine adjusting geardrive for microscopes which may be actuated manually by means of aplanetary gear drive or by a drive motor for automatic focusing. Theautomatic focusing is independent of the manual fine focusing by way ofthe planetary gear, but is effected through the same gear connection asthe coarse drive motion and requires a further helical gear and anadditional angular lever. The manual coarse and fine adjustments in thisknown apparatus require separate, parallel drive shafts.

SUMMARY OF THE PRESENT INVENTION

One object of the present invention is to provide a focusing drive for amicroscope in which both coarse and fine focusing adjustments can bemade easily.

Another object of the present invention is to provide a focusing drivefor a microscope wherein manual and powered focusing adjustments aremade independently of each other so that powered focusing will notdisturb the position of manual adjustment controls.

A further object of the present invention is to provide a focusing drivefor a microscope which includes a fine focusing adjustment which issimple in construction to eliminate sources of error and irregularitiespresent in complicated structures.

In accordance with the above and other objects, the present invention isa microscope having an adjustable portion and a focusing drive formoving the adjustable portion. The focusing drive includes manualadjustment means comprising a gear drive connected to the adjustableportion for moving the portion in response to manual actuation, andmotor means for moving the portion independently of the gear drive. Themotor drive means comprises a motor and a control element connecting themotor to the adjustable portion.

The focusing drive can include a guide plate mounted for slidingmovement, with the control element being mounted rotatingly in the guideplate, and means attached to the portion for contacting said controlelement.

In accordance with other aspects of the invention, the microscopecomprises a portion mounted for vertical movement to effect a focusingadjustment and a slide element mounted for vertical movement. A manualactuation means comprising a gear drive is connected to the slideelement for moving the slide element vertically in response to manualactuation. A motor drive means for producing powered movement of theportion, comprising a motor and a control element mounted to the slideelement and connected to the motor for movement by said motor, is alsoprovided. The control element contacts the portion to cause verticaldisplacemant of the portion in response to powered movement of thecontrol element produced by said motor.

In a preferred embodiment, the control element is a cam connected forrotation by the motor. Also, the gear drive includes a rack connected tothe slide element and a pinion gear meshing with the rack. Further, themicroscope can include a flexible shaft connecting the motor to thecontrol element.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more readily apparent from thedetailed description to follow wherein like elements represent likeparts throughout and in which:

FIG. 1 shows a fragmental longitudinal sectional view of a microscopewith a drive according to the present invention; and

FIG. 2 shows a sectional view taken along the line A--A of FIG. 1.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The microscope depicted fragmentally in FIG. 1 has a manually actuatedcoarse/fine gear drive designated generally by reference numeral 10.Gear drive 10 includes coaxial actuating knobs and generally correspondsto the known planetary gear described in the Leitz pamphlet "ThePlanetary Gear of the Orthoplan, a Precision Drive in MicroscopeConstruction", Insert to List 512-82b. For this reason a detaileddescription is omitted here. (Orthoplan is a registered trademark.)

The manually actuable gear drive 10 is stationarily mounted on themicroscope housing and transmits any manual adjusting movement to an endgear 11 which meshes with a toothed rack 15, mounted on a guide plate16. Guide plate 16 is supported slidingly in a vertical position by rods17. At its upper end the guide plate 16 is provided with a recess 18. Acontrol element 19 in the form of an eccentric cam is rotatingly mountedin recess 18 by a shaft 20, which is journalled in plate 16. One end ofshaft 20 is fixed to cam 19 and the other end of shaft 20 is connectedby means of a flexible drive shaft 22 to the drive shaft of adirectionally reversible motor 23. Drive shaft 22 includes alongitudinally extensible shaft connected at its end to a pair ofuniversal joints 21. A guide element in the form of a journal 25carrying a ball bearing 26 rests on the eccentric cam 19. Journal 25 isfixedly attached to the object holder 13 of a microscope stage 12.

During manual focusing, the end gear 11 of the gear drive 10 causes thetoothed rack 15 and the guide plate 16 to be adjusted vertically. Thevertical movement of the guide plate 16 is transmitted through thecontrol element 19 and the guide element 25, 26 to the object holder 13,thus causing the microscope stage to slide in guide rail 14. As can beunderstood from the above explanation, manual adjustment produces asimultaneous movement of the guide plate 16, the control element 19 andthe guide element 25, 26.

Fine focusing is effected by means of motor 23 which rotates controlelement 19 through drive shaft 22. Control element 19, it will berecalled, is rotatingly supported in the guide plate 16 only. Due to itseccentricity, rotation of control element 19 raises or lowers guideelement 25, 26 connected to the object holder 13, thereby resulting invertical adjustment of the microscope stage 12. The maximum adjustmentrange is determined by the throw of the eccentric cam chosen. Finefocusing with motor 23 does not affect the position of the gear drive 10or the vertical position of the guide plate 16.

Even though the embodiment in FIGS. 1 and 2 shows an object holder whichis moved in the vertical direction, it will be apparent that the driveaccording to the present invention may be used in the same manner toadjust a different stage of the microscope. Also, a cam of differentconfiguration may be used as the control element, for example, acardioid curve may be used. As another alternative, the cam could bepositioned in a recess in the guide rail 14, so that the guide railrests directly on the cam. A rigid drive shaft may also be used betweenthe motor and the control element, if the available space permits themotor 23 to be moved vertically together with the guide plate and thecontrol element.

A microscope equipped with the drive according to the present inventionis suitable for the continuous observation of nonplanar objects, i.e.objects having vertical irregularities, by virtue of the fact that finefocusing by the motor produces a scanning motion of the focus along theZ axis.

The foregoing description is presented for the purpose of clearlyillustrating the present invention. Numerous additional changes can bemade without departing from the scope of the invention as set forth inthe appended claims.

What is claimed is:
 1. In a microscope having an adjustable portion, afocusing drive for moving said adjustable portion, comprising:manualcoarse and fine adjustment means comprising a gear drive connected tosaid portion for moving said portion in response to manual actuation toeffect individual coarse and fine adjustments, said manual adjustmentincluding separate actuating knobs connected to said gear drive toeffect, respectively, said coarse and fine adjustments; and motor drivemeans for moving said portion independently of said gear drive, suchthat said gear drive remains stationary during actuation of said motordrive means, said motor drive means comprising a motor and a controlelement connected to effect movement of the adjustable portion inresponse to said motor.
 2. A focusing drive as set forth in claim 1comprising a guide plate mounted for sliding movement, said controlelement being mounted rotatingly in said guide plate, and means attachedto said portion for contacting said control element.
 3. A focusing driveas set forth in claim 2 wherein said gear drive comprises a toothed rackmounted on said guide plate.
 4. A focusing drive as set forth in claim 1wherein said separate actuating knobs connected to said gear drive arearranged coaxially.
 5. A focusing drive as set forth in claim 1 whereinsaid motor drive means comprises a flexible drive shaft connecting saidmotor to said control element.
 6. A microscope as set forth in claim 5wherein said control element comprises an eccentric cam connected to berotated by said flexible shaft, and a guide element connected to saidadjustable portion and positioned to move in response to rotation ofsaid eccentric cam.
 7. A focusing drive as set forth in claim 1 whereinsaid adjustable portion is mounted for vertical movement.
 8. Amicroscope as set forth in claim 1 wherein said control elementcomprises an eccentric cam.
 9. A microscope, comprising:a portionmounted for vertical movement to effect a focusing adjustment; a slideelement mounted for vertical movement; manual coarse and fine actuationmeans comprising a gear drive connected to said slide element for movingsaid slide element vertically in response to manual actuation to effectindividual coarse and fine adjustments, said manual adjustment includingseparate actuating knobs connected to said gear drive to effect,respectively, said coarse and fine adjustments; and motor drive meansfor producing powered movement of said portion independently of saidgear drive such that said gear drive remains stationary during actuationof said motor drive means, comprising a motor, and a control elementmounted to said slide element and connected to be moved by said motor,said control element contacting said portion to cause verticaldisplacement of said portion in response to powered movement of saidcontrol element produced by said motor.
 10. The microscope as set forthin claim 9 wherein said control element is a cam connected for rotationby said motor.
 11. The microscope as set forth in claim 9 wherein saidgear drive includes a rack connected to said slide element and a piniongear meshing with said rack.
 12. The microscope as set forth in claim 9including a flexible shaft connecting said motor to said controlelement.